how many ounces (oz) there are in a gallon of water depends on where in the world you are. You see, the US liquid gallon measures less (3.785 liters) than the UK imperial gallon (4.546 litres). You should probably bear this in mind when thinking about daily water intake because there’s a big difference between the two (you could be drinking 3/4 of a litre more water if you use the UK imperial gallon conversion). If you want the conversion in cups, by the way, do take a look at this post on gallons and cups.
When converting to ounces (fluid ounces), you need to bear in mind that the US fluid ounce measures more than the UK imperial fluid ounce. The US fluid ounce measures 29.5735mL . By comparison, the UK (imperial) fluid ounce measures 28.4131mL. To assist you, I’ve included the two conversions of gallons to ounces below.
I’ve included two table of conversions to help you see how many fluid ounces there are in a gallon – one using US and one using UK measurements. For converting a specific number of gallons to ounces, use our converter tool.
Gallons (US)
Ounces (US)
Liters
1
128
3.785
2
256
7.571
3
384
11.356
4
512
15.142
5
640
18.927
6
768
22.712
7
896
26.498
8
1024
30.283
9
1152
34.069
10
1280
37.854
11
1408
41.64
12
1536
45.425
13
1664
49.21
14
1792
52.996
15
1920
56.781
Gallons (UK)
Ounces (UK)
Litres
1
160
4.546
2
320
9.092
3
480
13.638
4
640
18.184
5
800
22.73
6
960
27.277
7
1120
31.823
8
1280
36.369
9
1440
40.915
10
1600
45.461
11
1760
50.007
12
1920
54.553
13
2080
59.099
14
2240
63.645
15
2400
68.191
If you would like some more help with converting between gallons and ounces, give our liquid volume converter a try. We also have an article about how to convert cups to ounces and vice-versa.
